The present invention relates generally to the field of removable computer data cartridges. More particularly, the present invention relates to a disk cartridge wherein an integral display indicates the remaining storage capacity available on the cartridge.
Monitoring the storage capacity remaining on a conventional disk cartridge requires that the cartridge be inserted into a disk drive and accessed by a computer. Where a large number of cartridges are used, searching for a cartridge with adequate remaining capacity to store a file is cumbersome.
If a disk is selected that has slightly less remaining capacity than is required to store a large file, a "disk full" message may not appear until almost the entire file is written to the disk. For many applications, particularly using the MSDOS operating system, files may not span the end of a disk. Partially written files are therefore lost.
This problem is especially critical where files are transferred via modem. Large files take a significant amount of time to transfer and the entire file iady be lost if the transfer is interrupted before completion because the storage cartridge is full.
As the storage capacity and access speed of disk cartridges increase so does their cost. More efficient use of disk cartridges is desirable to reduce the overall cost of data storage.
A device has been proposed that would allow users to determine the remaining storage capacity on a computer disk without having to insert the disk into a computer. U.S. patent application No. 08/778,604 describes a disk cartridge with a mechanical pointer visible to the user. The pointer is positioned by a mechanical actuator located in the disk drive of a computer. As data is written to, or deleted from, the disk the actuator moves the pointer to indicate the storage capacity remaining on the disk. When the disk is removed from the disk drive the user can inspect the pointer to see how much space remains on the disk.
The above-identified system of suffers from several drawbacks. Impact to the disk housing many cause inadvertent movement of the pointer resulting in an incorrect capacity reading. The addition of mechanical parts to both the disk cartridge and the disk drive is undesirably complex, particularly in small notebook or palm-top computers where space is at a premium. Accurately judging the amount of storage capacity on a disk by the position of a small pointer is difficult.